Borderline personality disorder (BPD) is often comorbid with disordered eating behaviors. Effective treatments are critically needed for this complex population. Mindful movement interventions may represent a promising, adjunctive treatment option for individuals with BPD symptoms, especially those with co-occurring disordered eating. Previous work has demonstrated that Taekwondo, a Korean martial art emphasizing mind–body connections, is an acceptable and feasible candidate intervention. This pilot study (N = 24, 79.2% female, Mage = 31.2; 75.0% white) examined acceptability and feasibility of a Taekwondo and Mindfulness intervention in a Dialectical Behavior Therapy (DBT) intensive outpatient program (IOP) using a within-subjects design. Patients consistently rated Taekwondo groups highly regarding average satisfaction and effectiveness (3.6–4.7/5), and showed significant state-level improvements in anxiety (p = 0.001. d = 0.76), sadness (p = 0.002, d = 0.74), happiness (p < 0.001, d = −0.86), and relaxation (p < 0.001, d = −0.96) following group participation. Conversely, significant changes in sadness (p = 0.082, d = 0.40) and happiness (p = 0.078, d = −0.41) were not observed following Comparison Groups (Traditional Mindfulness). Binge-eating frequency was correlated with greater reductions in sadness (r = 0.43, p = 0.041) following Taekwondo groups, but not Comparison Groups (r = 0.01, p = 0.977). Compared to non-purging individuals, patients reporting purging showed greater increases in happiness following Taekwondo groups (p = 0.024, d = 1.23), but smaller increases following Comparison Groups (p = 0.037, d = −1.24). Together, preliminary findings suggest an additive benefit of Taekwondo as a mindful movement adjunct to treatment.